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61.
依据反射或检基原理,本文提出用于截尾资料的两样本队列半数生存期(CHL)检验.两样本合并CHL经指数内插取自Kaplan-Meier或Berkson-Gage估计值.连续性校正,经以有效样本容量取代样本容量,扩展自Yates校正.合并标准误来自同源性生存率方差估计值,后者经有效样本容量扩展自二项分布方差.无截尾时,这些统计量还原为经典中位数检验.与反射统计量相比,检基统计量具有更高的功效.附有工作实例描述其临床应用. 相似文献
63.
64.
近年来,用微波感偶氩等离子体(Ar-MIP)作为原子发射光谱分析激发源已由实验研究进入实用阶段。据报道,Ar-MIP对气体、卤素和金属元素都有很高的检测灵敏度,与其它等离子体光源比较,有气体消耗量小,微波工作功率低和对冷却条件要求低 相似文献
65.
66.
Confined thin film melt polymerization (CTFMP) of naphthalene chloride/hydroquinone (NCMQ, 1/1, molar)mixtures at polymerization temperatures (T_p) below ca. 300℃ resulted in relatively thick, elongated crystals. Polymerizationof NC/HQ above 300℃ between glass yielded well-formed lamellar crystals ca. 100 A thick. Phase Ⅰ and Ⅱ [001] EDpatterns were obtained for all T_p, the relative amount of phase Ⅰ increasing with T_p. Polymerization of naphthalenedicarboxylic acid/hydroquinione diacetate 1/1 mixtures at high T_p also yielded lamellar crystals that "curled up" off of thesubstrate. When the high temperature CTFMP polymerization was conducted between mica, aggregates of lamellae on-edgedeveloped but epitaxial growth did not occur. Epitaxial growth of lamellae between mica could be obtained, however, byconfined thin film solution polymerization, with both of the latter samples yielding apparently related ED patterns from adifferent unit cell than phase Ⅰ or Ⅱ. Fiber patterns, obtained from sheared samples, indicated considerably greater crystaldisorder than in the nascent crystals. Refinement of the phase Ⅰ unit cell parameters, based on the [001] and [01 1] EDpatterns, with modeling based on Cerius~2, suggests a monoclinic phase Ⅰ unit cell with a = 7.76, b = 5.71, c = 14.99 A, α = γ= 90°, β= 99.7°, ρ = 1.47 g/cm~3, space group P12_1/al. 相似文献
67.
We present and study a fractal model of a non-uniform granular system for the first time, based on which wenumerically solve the dynamics actions in the system successfully in one-dimensional case. The multi-mixture is composed of N different particles, whose granularity distribution has the fractal characteristic. The particles are subject to inelastic mutual collisions and obey to Langevin equation between collisions. Far from the equilibrium,i.e. the given typical relaxation time τ of the driving Brownian process is much larger than the mean collision time τc, the results of simulation indicate that the degree of inhomogeneity in the granularity distribution signed by the fractal dimension D of size distribution has great influence on the dynamics actions of the system. The velocity distribution deviates obviously from the Gaussian distribution and the particles cluster more pronouncedly with the larger value of D in the system. The velocity distribution and spatial clnsterization change with D are presented. 相似文献
68.
雷震洲 《通信技术政策研究》2005,(1):9-15
目前,网络正在走向下一代。下一代网只是一种新的技术手段,提供下一代服务才是真正的目的。本文分析了下一代服务的内容与特征及脚6与下一代服务的关系,对我国应如何研究开发RFID标记和脚6提出了几点建议。 相似文献
69.
双归属(dualhoming)雷震洲(邮电部科学技术情报研究所北京100083)通信公司为了向用户提供足够高的服务能力(serviceability),也就是使用户对所提供的服务有很高的满意度(customersatisfaction),必须在一开始... 相似文献
70.
Based on the anisotropic Seebeck tensor coefficients, a light-thermo-radiation detector made of high-Tc superconductor (YBa2Cu3O7-δ) was fabricated, which can function at room temperature. The induced voltaic signals at various modulation frequencies for radiation from He-Ne laser and from a 500 K black body were measured. The noise ratio for detecting He-Ne laser radiation and the D* for black body were evaluated. Compared with bolometer made of high-Tc superconductor which functions at liquid nitrogen, and with pyroelectric detector, it was found that the advantages of this new device are that the device can work at room temperature with very low noise and very fast response. Although having a lower D* value than that of bolometer for the present device construction, we point out the possibility and the direction for improving the D* value, hence the promising prospect of this kind of device. 相似文献